Hamadryas Baboons, Papio hamadryas: Captive vs. Wild

As I headed to the exhibit where the hamadryas baboons (Papio hamadryas) resided, I knew something interesting would happen over the next few hours. As I walked into the exhibit, I found two mothers pulling their infants' tails to keep them from straying. This particular act reminded me of how some parents put leashes on their children so they won't wander too far. This example demonstrated how similar the behavior of hamadryas baboons and humans can be.

Throughout my life I have enjoyed observing animals and the way they interact with their surroundings. Walking through parks I have watched squirrels, birds and other animals, always curious to know what their actions meant. Consequently, when I had the opportunity to study the hamadryas baboons at the Prospect Park Zoo, I decided to focus my research on their behavior.

When I visit zoos, I always wonder how much the animals' behavior is affected by their captivity. So I decided to conduct a comparative study that contrasted the research of the primatologist Larissa Swedell on hamadryas baboons in the wild to a behavioral study of the hamadryas baboons at the zoo. There were two main goals for this study. The first was to compare the behavior of hamadryas baboons in the wild to those of captive baboons. The second goal was to investigate which behaviors occurred the most frequently in the captive group.

HYPOTHESES AND PREDICTIONS

The null hypothesis for my first question is that there will be no differences in the behaviors of captive hamadryas baboons compared to wild hamadryas baboons. My alternative hypothesis is that there will be differences in some of the behaviors of captive hamadryas baboons compared to wild hamadryas baboons. The independent variables were wild and captive hamadryas baboons, and the dependent variable was their behavior.

My null hypothesis for the second question is that no one behavior will occur more frequently than any other behavior among the captive baboons at the Prospect Park Zoo. My alternative hypothesis for the second question is that grooming will occur more frequently than any other behavior exhibited by the captive baboons. The reason I predicted grooming as the most frequent behavior is because baboons groom each other to create better relationships with the members of the troop (Flannery). Also, while grooming, baboons reciprocate and groom each other. So I predicted that grooming would be the behavior most often observed among the captive baboons.

PROCEDURE

I observed 10 captive hamadryas baboons that were separated into two troops at the Prospect Park Zoo. To answer my first question, I used a checklist to observe their behaviors and later compared these behaviors to a checklist compiled by primatologist Larissa Swedell when she studied wild hamadryas baboons in the lowlands of the Northern Rift Valley in Ethiopia (Swedell 2006).

For my second question, I collected data about the frequency of behaviors performed by the captive baboons at the Prospect Park Zoo. I divided baboon behaviors into four major categories: sitting, grooming, eating and walking.

I conducted my observations over six days, for four hours each visit, for a total of 24 hours of observation. I arrived early (when the zoo opened) in order to see the first troop on exhibit, which consisted of one alpha male, one dominant female, two mothers and two infants. When I arrived, I identified each individual before starting my observations. Identification was determined by looking at their size and their injuries. One of the female baboons was easy to identify because she did not have a baby. The alpha male was easy to identify because of his large size and the abundant fur on his back.

After learning their identities, I wrote their names in a chart in my field journal. I started with the alpha male simply because he was the easiest to locate. I started my stopwatch and jotted down his behavior for continuous 30-second intervals. After 15 minutes, I stopped my observations of the male. Then I repeated the same steps for another of the baboons. When I was finished with the first troop, I stopped for the morning and waited until the afternoon for the second group to come out on exhibit.

Henry familiarizes himself with the hamadryas baboons at an exhibit at the American Museum of Natural History.

In the second troop, there was one alpha male, another male and four females. Once again, I identified each individual before starting my observations. Then I started with the alpha male and recorded his behaviors for 15 minutes for continuous 30-second intervals. When I finished with the alpha male, I moved on to the other five baboons in the troop. During each expedition, I videotaped the baboons using a Panasonic camcorder, which allowed me to review and record any behaviors I might have missed.

BACKGROUND RESEARCH

Hamadryas baboons live throughout Africa but mainly in Ethiopia (Swedell 2002). During the day hamadryas baboons prefer to reside in trees, and at night they sleep on the cliffs (Kummer 1968). Hamadryas baboons are known as "desert baboons" because of their environment. In the past they were known as "sacred baboons" because the Egyptians considered them sacrosanct (Ho 2009). Males usually weigh 20 to 30 kilograms while females weigh 10 to 15 kilograms (Flannery).

Simen, a 19-year-old Alpha Male

In hamadryas baboons there are four hierarchy groups: the harem, the clan, the band and the troop. A harem consists of a male and a few females. A clan is a group of harems joined together, while a band is a group of clans joined together. Several bands form a troop (Flannery).

Males stay in the same clan throughout their lives. One male might have a harem of up to ten females. Usually when a new male becomes the leader, he will kill all the infants in order to make the mothers go back into estrus, which is a period during which a female is able to conceive. If an alpha male has fewer females, the time that a female spends grooming the alpha male increases. On the other hand, if the alpha male has more females in his harem, then the time that a female spends grooming the alpha male will decline (Ho 2009).

A male hamadryas baboon grooms a female at the Prospect Park Zoo.

According to Kummer's observations in a classic study (1968), females generally do not groom each other unless they are related to each other. Sometimes the females will not groom one another because the alpha male doesn't allow it in his group. Other than grooming, other common behaviors within the harem include resting, foraging or traveling. During Swedell's field study (2006), she observed and recorded 67 different behaviors from the hamadryas baboons in Ethiopia. The main categories for these behaviors were: grooming, movement of baboons, aggressive behaviors, sexual behaviors, communication, eating, resting, and traveling.

The primary goal of this study was to compare the behaviors of baboons observed in the wild to the behaviors of captive baboons in a zoo. Of the 67 behaviors the primatologist Larissa Swedell observed in her study of wild hamadryas baboons (2006), 57 of these behaviors were also observed in captive hamadryas baboons at the Prospect Park Zoo. Based on the data I collected, captive and wild hamadryas baboons shared approximately 85.1 percent of behaviors (see Figure 1). On the other hand, there were 10 behaviors, or approximately 14.9 percent, that were observed in the wild by Larissa Swedell but not observed in the captive baboons. These behaviors were: mounting, intromit, thrust, presumed ejaculation, confirmed ejaculation, hit, fight, countercharge, aid, and keck. There were no observed behaviors that were unique to the captive setting.

The second goal of this study was to investigate which behaviors occurred the most frequently in a captive group of baboons. I spent 545 minutes observing the baboons and recording their behavior (see Figure 2). During my observations, hamadryas baboons spent 328 minutes, or approximately 45 percent of their time, sitting. Grooming occurred for 260.5 minutes, or 35 percent of their time, while walking occurred for 102.5 minutes, or 14 percent of their time. Finally, the baboons spent 46.5 minutes, or 6 percent of their time, eating. Please note that these observations were continuous; therefore, on occasion, two or more activities are recorded in the 30-second interval. Consequently, the total amount of minutes added together exceeds 545 minutes. Based on the data collected, the two most common behavior categories were sitting and grooming.

CONCLUSION

In this investigation, the alternative hypothesis for my primary question was that there are differences in some behaviors of captive hamadryas baboons compared to wild hamadryas baboons. Based on the data collected, the results support my alternative hypothesis. This is because there were ten behaviors that were unique to Larissa Swedell's wild study (2006) compared to my captive study at the Prospect Park Zoo. The behaviors that weren't observed in the captive hamadryas baboons were mainly sexual and active behaviors. The sexual behaviors that were not observed were because the females were not in estrus. Two of the mothers in the first troop had newborn infants, and in the second troop the females were older and may have been past the reproductive stage of their life cycles. The aggressive behaviors that were not observed may be because the troops were on exhibit during separate schedules, which eliminated competition between them.

The alternative hypothesis for my secondary question was that grooming would occur at a higher frequency than any other category of behavior exhibited by the captive baboons at the zoo. Based on the data collected, (see Figure 3) the results do not support my hypothesis. In this investigation, it turns out that hamadryas baboons spend the highest proportion (45 percent) of their time sitting. This may be because there is limited space in the exhibit.

Also, I made my observations during relatively warm temperatures, which may have inhibited the movement of the baboons.

Figure 3: Frequency of Behaviors Performed by Captive Baboons at the Prospect Park Zoo

If I were to undertake this study again, I would make sure that I knew how to exactly distinguish each baboon before gathering my data. While I was collecting data, I sometimes found it difficult to differentiate among the baboons. The females in particular looked very similar and were difficult to identify. Luckily, there were often volunteers available at the exhibit to help me distinguish each of the baboons.

Another thing that I would like to improve in the future is to be more careful when recording data. In my initial ethogram I was missing some data, probably due to carelessness. The first three days were especially confusing. However, the more I observed the baboons, the easier it became to distinguish them and record the data accurately.

By studying the differences in behaviors between captive and wild hamadryas baboons, I hope that I have provided useful information for a zoologist or for anyone interested in knowing more about these animals. As animals around the world become increasingly endangered, the need for zoos and conservation parks becomes more and more important. Captive baboon studies like the one I completed make data available that may help zoos be better informed about captive baboon behavior and provide insight into how to design suitable habitats.